A290869 - OEIS

A290869

Numbers that are repdigits with length > 2 in more than two bases.

4095, 32767, 65535, 67053, 262143, 265720, 531440, 1048575, 2097151, 4381419, 5592405, 7174453, 9808617, 11184810, 13938267, 14348906, 16777215, 19617234, 21523360, 29425851, 39234468, 43046720, 48686547, 49043085, 58851702, 61035156, 68660319, 71270178

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Most of the terms of A167783 are repdigits with length > 2 in only two bases.

For any b > 1 and k > 2, b^(4*k)-1 is a repdigit with length > 2 in bases b, b^2 and b^4; hence this sequence is infinite. - Rémy Sigrist, Aug 19 2017

LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..777

Rémy Sigrist, C# program for A290869

Rémy Sigrist, C++ program for A290869

EXAMPLE

67053 is a repdigit with more than 2 digits in three bases: [31,31,31]_46, [21,21,21]_56, [3,3,3]_149.

PROG

(PARI) isok(n)=my(nb = 0); for (b=2, n-1, d = digits(n, b); if ((#d > 2) && (#Set(d) == 1), nb++); if (nb > 2, return (1)); ); return (0);

(C#) See Links section.

(C++) See Links section.

CROSSREFS

Subsequence of A167783.